1. Field of the Invention
The present invention relates generally to cooling electrical power sources and, more particularly, is concerned with internally-located rotating unions used to supply and discharge liquid coolant to and from a rotor shaft of a motor-generator set.
2. Description of the Prior Art
Generally, internal circulation of liquid coolant through rotor shafts of turbine generators and motors to cool the same as they are rotating at high speed is a conventional practice. Many different designs of connections or joints for introducing the liquid into the rotor shafts and discharging it therefrom are known in the prior art. Representative of the prior art are the joints disclosed in Turner et al U.S. Pat. No. 2,504,094, King, Jr. U.S. Pat. No. 2,884,285, Krastchew U.S. Pat. No. 3,240,967, Smith, Jr. et al U.S. Pat. No. 3,845,639, Albaric et al U.S. Pat. No. 4,114,059, Pouillange U.S. Pat. No. 4,207,745, Okamoto et al U.S. Pat. No. 4,358,937, Zerlik U.S. Pat. No. 4,384,222 and Wieland U.S. Pat. No. 4,574,210. Also, many different versions of both external and internal (in-the-shaft mounted) rotating connections or joints, generally referred to as rotating unions, are manufactured by Deublin Company and Johnson Corporation.
While the many connections or joints of the prior art, such as those of the aforecited patents and those available from the aforementioned companies, would appear to operate reasonably well and generally achieve their objectives under the range of operating conditions for which they were designed, most seem to be unsuitable for delivering and discharging water coolant into and from the central shaft of a motor-generator set used in a nuclear submarine. Particularly, prior art designs would appear to have shortcomings in terms of one or more of the following criteria: resistance to shock loads, mechanical design simplification, reduced overall weight and volume, and maintenance requirements.
Consequently, a need exists for a rotating union design which will accommodate liquid coolant delivery and discharge into and from the motor-generator set rotor shaft in a manner which meets the aforementioned design criteria.